Process of dehydrating emulsions



F. W. HARRIS.

PROCESS OF DEHYDRATING EMULSIONS.

APPLICATION FILED AUG.4. 1919.

RENEWED MAY 31,1921- 2 SHEETS-SHEET I.

Patented Jan. 31, 1922.

INVENTOR. 1 mm WHA REVS,

BY%IZW4%;

ATTORNEY.

F. W. HARRIS. PROCESS OF DEHYDRATING EMULSIONS. APPLiCATlON manAUG.4.1919. RENEWED MAY 31.1921.

1,405,127, Patented Jan. 31, 1922.

I 2 SHEETS-SHEET 2 INVENTOR. Foko VV. HARRIS,

ATTORNEY.

mm -STATES' T NroFncE.

( FORD W. HARRIS, OF LOS ANGELES, CALIFORNIA, ASSIGNOR TO PETROLEUMRECTIFYING COMPANY, OF 01 CALIFORNIA.

PROCESS OF .DEHYDRATING EM'IILSIONS.

Specification of Ietters Patent.

SAN FRANCISCO, CALIFORNIA, A CORPORA'I'I'ION Original application filedMay 12, 1919, Serial No. 296,641. Divided and this application filedAugust 4,

1919, Serial No.'815,347. Renewed To all whom it may concern:

Be it known that I, Fom) W. HARRIS, a citizen of the United States,residing at Los Angeles, in the county of Los Angeles and State ofCalifornia, have invented a new and useful Process of DehydratingEmulsions, of which the following .a specification.

My invention relates to the art of dehydratlng petroleum emulsions.Petroleum oils as found in nature often contain water which may bearbitrarily classified as free water. or trapped water. practice in theart to allow the oil to stand in sumps or in tanks for the purpose ofallowing the Water to settle out, and a great deal of the water found inthe oil may be separated. It is common practice in the art to designatethe water which will be settled out by gravity within a few days as freewater.

, In addition to the free water there'is often a considerable quantityof water in the oil which will not settle out within a reasonable time,this water being ordinarily found in the form of small or evenmicroscopic particles or globules. This emulsified water may beconveniently designated as trapped water. There is of course no sharpline of. demarcation-between trapped water and free water, the wateroften bein'g found in all sizes of globules from the microscopicallyminute to particles which are easily visible to the naked eye.

It is the object of my invention to provide a process by Whichpractically all water, whether trapped or free, may be readily removedvfrom petroleum oils.

. Further objects and advantages will be made evident hereinafter.

Referring to the drawings which are for illustrative purposes only,

Fig". 1 is a sectional elevation of my inven-' tion.

Fig. 2 is a plan on line 2-2 of Fig. 1 as viewed from above.

Fig. 3 is a plan on line 33 of Fig. 1 as viewed from above.

In the form of apparatus used to carry on my invention illustrated inthe drawing, I provide a tank 11 having a tight bottom 12 and a tighttop 13. Secured 1n a flange 14 near the bottom thereof, in an inlet pipe15 which extends across the tank and is pro- May 31, 1921. Serial 170473373.

I vided with a plurality of small openings 16.

The How of oil through the inlet pipe is controlled by a valve 17. isprovided at the apex of the top 13 which may be conveniently ofcylindrical or conical contour. A steam coil 19 may be placed inside thetank directly above theinlet pipe 15 and a water gauge 20 may be placedabove the side of the tank for indicating difl'erences in oil levelbetween planes a--a an 72-12. It is common Secured considerably abovethe plane a a, which represents the maximum water,

level, is a plurality of grounded electrodes 25, the electrodes shownbeing flat plates secured on pipe members 26 carried in suitablebrackets 27 fixed to the tank. All the plates are mechanically andelectrically connected together and form what may be termed the groundedelectrode. A plurality of plates 30 are supported on pipe members 31which are carried on insulators '32 which are in turncarried on suitablemembers 33 fixed to the tank. The plates 30 are mechanically andelectrically connected together and form what may be termed the liveelectrode. The plates 30 extend downwardly parallel to and equallyspaced from plates 25, forming with the plates 25 an electric field inwhlch the.

dehydration is carried on. An insulator 40 is secured in the top of thetank, this insulator being preferably formed of porcelain and beingpressure Patented Jan. 31,1922.

An outlet pipe 18- tight, a conductor passing through and be- *ingconnected through a wire 42 with the plates 30. A transformer 50 isprovided, the high tension secondary 51 thereof being connected at oneside to the tank 11 at 52, and at the other side to the conductor 41.primary 53 of this transformer is connected to one of the stationarycontacts 54 of a safety switch 55. This safety switch is provided withabridging contact 56 which connects the two stationary contacts 54together. The other contact 54 is connected to a resistance 57. I Theresistance 57 and the other side of 58 of the primary 53 are connected.to a control switch 59 'by means of which The they may be connected tosupply mains 60.

The bridging contact 56 is operated by means of a rod 61 which passesthrough a 56 being pulled into contact with the members 54 when thefloatassumes its extreme top position. This float is so placed that itrises to the highest part of the tank and tends to open the circuitbetween the contacts 54 at all times that the tank is not entirelyfilled with liquid by moving the bridge member 56.

A water outlet 70 is provided, this water outlet rising inside a draincolumn 71 which is connected to a drain 72 and being provided at itsupper end with a long threaded sleeve 73 which can be-moved up and downon the pipe 7 0 so as to change the upper level of the sleeve 73 asshown at 0-0. A valve 80 is placed in the pipe 18, by-means of whichpressure may be maintained on the tank 11.

The method of operation of my invention is as follows:

Oil under pressure is delivered through the valve 17 to the interior ofthe pipe and passes through the perforations 16 therein rising through abody of water which has been placed in the bottom of the tank, the

level of this water being easily observed by means of the gauge glass 20and the height thereof being regulated by the members 70 to 7 3somewhere between the levels a-w and 5-6, as will hereinafter beexplained. This entering oil may contain both free and trapped water.The body of water into which the oil is injected is preferabl heated bymeans of the steam coil 19 to acilitate the separation of the free waterfrom the oil, this separation taking place as the oil rises throu h thebody of water, the purpose of the perfgn ations 16. being to finelydivide theoil into a plurality of small streams from which the freewater particles readily separate, attaching themselves to the body ofwater and forming a portion thereof. If

in a body of oil which contains little or no free water, the free waterbeing caught and removed, as has just been explained, by the body ofwater in the bottom of the tank. An electric potential is maintainedbetween these plates due to thesecondary 51 of the transformer 50. Thispotential causes electrio currents to flow through the emulsion "betweenthe plates and may conveniently have a magnitude somewhere between 5,000

and 20,000 volts.

For the purpose of preventing sparks in the tank, when it is partiallyfilled with oil. thus having a body of gas and air the top, the safetyswitch 55 is prpvided, this safety switch only closing the circuit tothe primary 53 of the transformer 50 when the tank is entirely filled,and opening it whenpipe, the upper level 0-0 of which can be readilyregulated; As this-pipe is in com- Y munication with the water in thebottom of the tank, it is all times filled with water and the column ofwater so formed is balanced against the combined water and oil insidethe tank and the pressure produced by the valve 80. As a result of thedifference in gravity between the oil and water, there is a tendency forwater to overflow or to rise above the level 00 whenever the water inthe tank rises above the level H, the level of water falling below thelevel 6-5, whenever the water in the tank falls below the level b-b. Inthe event that water is supplied through the pipe 15 it is automaticallydrawn oil through the pipe as soon as sufficient accumulates to raisethe level in the bottom of the tank to the It will be seen that myinvention difiersradically from the previous art. It is a well knownfactthat by passing an electric current through a body of emulsion one isable to change trapped water into free water.

In the patents'to Frederick G. Cottrell, Nos. 987,114, 987,115, 987,116,987,117, and 994,37 7, a general theory of the action of electricaldehydrators is set forth. This theory is, in short, that upon theimpressing of an electric motive force between electrodes immersed inoil there will inevitably result a number of water chains, thesupposition being that the small water particles line themselves up inmore or less continuous lines. 4

It is considered by Cottrell and others that the passage of currentacross these chains tends to break thev oil film between the waterglobules and to cause them to coalesce into larger masses. I am not surewhether this action actually takes place or not. I am, however, surethat it is highly desirable to form a large number of the chains, and Iam further sure that these chains when formed have a strong attractionfor each other, which, to my mind, fully accounts for the coalescingaction which I believe to be merely the union of a large number ofchains of trapped particles into one chain in which all or part of theindividual particles may be large enough to be designated as free water.

I have further found the principal problem in the dehydrating of oil isto prevent the introduction of masses of free water into the fieldbetween the electrodes. It will be noted that in my dehydrator a body ofwater is maintained in the bottom and all entering liquid must passthrough this water. It will be further noted that by so passing theentering liquid I am able to catch and separate free water particles andthus prevent them from getting into the space between the electrodes.

I have further found that there is a continuous and rapid circulationaround the plates 25 and 30 of my dehydrator, the oil rising rapidythrough the space between the outside plates and the walls of the tank11. This is due in part to the cooling action of the outer walls of thetank 11 which causes a slow settling of the oil near these walls, thisoil being replaced by hot oil which rises between the plates 25 and 30.The circulas tiOn is further promoted by the formation of gas bubblesbetween the plates 25 and 30 which in rising greatly assist incirculating the liquid.

I have further found that any water particles which are of suflicientsize to be designated as free water seem to be caught at the lowestpoint of travel of the circulating oil, or perhaps continue to falluntil they reach the body of water in the bottom of the tank. In anycase I have found that it is unnecessary to provide any means forpreventing the formation of water chains as set forth in the Cottrellpatents, and I have further found that after a short period of operationthat the body of oil above the water is largely dehyrdated so that atits worst it contains only a few per cent of water.

I have further found that there is a stratification of the oil, the dryand clean oil rising to the top and passing out through the outlet 18. Ihave been able in actual practice with a dehydrator of this type toremove all the water but a small fraction of one per cent from a verystubborn emulsion.

In the operation of all previous commercial types of dehydrators, it hasbeen common practice to dehydrate the oil in open tanks. As there issome liability of sparks passing across the tops of the liquid in suchtanks and as the mixture of oil, gas and air in the top of such tanks ishighly inflammable, a considerable number of fires have resulted andthere have been large property losses and some loss of life due to theoperation of these open type dehydrators. I have found that it isentirely practical and indeed desirable to operate in closed tanks whichare entirely filled with oil. It will be noted that in my dehydrator theoutlet pipe is taken out of the extreme top and the safety switch isprovided so that there is no potential on any parts inside thedehydrator except when it is practically filled with oil. It istherefore impossible for explosions or fires to occur.

I have further found that it is highly desirable to keep the valve 80partially closed for the purpose of maintaining a pressure upon theinterior of the dehydrator. This I believe is due to the fact that thereis a tendency for gas bubbles to form in the space between the plates 25and 30 and by main- -taining a pressure on the oil the formation ofthese bubbles is somewhat retarded.

This application is a division of Serial 296,641, filed by me May 12,1919.

I claim as my invention:

A process of dehydrating emulsions which comprises establishing a bodyof dry oil in a tank and within a fluid of electrolytic stress;injecting wet oil into said tank and establishing a circulation to mixsaid wet oil with said dry oil by means of heating devices properlysituated in said tank.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 21 100 dayof July 1919.

FORD W. HARRIS.

